Improved active clamped ZVS buck converter with freewheeling current transfer circuit

An improved active clamped zero-voltage switching (ZVS) buck converter with freewheeling current transfer circuit is proposed in this study. Comparing with the traditional active clamped ZVS buck converter, the current of freewheeling diode, the clamping voltage and duty cycle loss are all halved. The reduced current and voltage stress will result in high reliability and efficiency. Moreover, the reduced duty cycle loss will result in a low input voltage. In the improved converter, a small inductor and an auxiliary diode are added to build the freewheeling current transfer circuit. The operating principle of the improved converter is described. The analysis and design considerations of the proposed converter are given. A 1.2 kW prototype converter is set up to validate the improved converter.